Hexapod type simulator assemblies are known and for example described in U.S. Pat. No. 3,577,659 and US2007/0059668. Such assemblies, which are capable of moving within six degrees of freedom, are also referred to as Stewart platform. These platforms are typically used for flight simulation to train pilots. US2007/0059668 describes a displaceable motion platform supported by six linear actuators. The six actuators are fixed at their upper end to a bearing block. The bearing block comprises resilient material to avoid vibrations. The bearing blocks themselves are bolted to the lower side of the motion platform itself.
U.S. Pat. No. 3,577,659 also illustrates an assembly wherein six actuators are coupled to the lower side of a load bearing structure by means of six three-degree-of-freedom movement joint.
Commercially available Stewart platforms, like for example the platforms obtainable from Moog (see http://www.moog.com/products/motion-systems/motion-bases/) all have a mount for receiving a joint, wherein the mount is fixed to the lower side of a load bearing structure.
A disadvantage of the known six-degree-of-freedom motion simulator assembly is that the centre of gravity of the total assembly is relatively high. Especially when large cabins such as shown in FIG. 5 of US2007/0059668 are placed on top of the load bearing structure the centre of gravity will be at a relatively high elevation relative to the base. The higher the elevation of the centre of gravity the higher the forces exercised on the actuators will be. There is a continuous desire to limit the elevation of the centre of gravity since these types of platform were first developed in the 1970's.